x <- rbinom(1000, 8, 0.5)
hist(x)

sum(x<3)/1000
## [1] 0.152
x[1:20]
##  [1] 2 3 3 4 5 3 3 4 7 4 5 4 3 4 2 4 3 2 4 6
library(rjags)
## Warning: package 'rjags' was built under R version 3.4.3
## Loading required package: coda
## Warning: package 'coda' was built under R version 3.4.2
## Linked to JAGS 4.3.0
## Loaded modules: basemod,bugs
#Model is defined as a string
modelclass.bug <- "model {Y ~ dbin(0.5,8) 
P2 <- step(2.5-Y)
}"
modelclass_11 <- jags.model(textConnection(modelclass.bug))
## Compiling model graph
##    Resolving undeclared variables
##    Allocating nodes
## Graph information:
##    Observed stochastic nodes: 0
##    Unobserved stochastic nodes: 1
##    Total graph size: 6
## 
## Initializing model
#Gibbs sampling for 1000 iterations
mcmc <- update(modelclass_11, n.iter = 1000, progress.bar = "gui")
test <- coda.samples(modelclass_11, c("P2" , "Y"), n.iter = 10000)
summary(test)
## 
## Iterations = 1001:11000
## Thinning interval = 1 
## Number of chains = 1 
## Sample size per chain = 10000 
## 
## 1. Empirical mean and standard deviation for each variable,
##    plus standard error of the mean:
## 
##      Mean     SD Naive SE Time-series SE
## P2 0.1451 0.3522 0.003522       0.003522
## Y  3.9961 1.4104 0.014104       0.014104
## 
## 2. Quantiles for each variable:
## 
##    2.5% 25% 50% 75% 97.5%
## P2    0   0   0   0     1
## Y     1   3   4   5     7
plot(test)